Firefox: Find Suggest is a free offering from Mozilla Labs that adds in search term suggestions to your in-text browser searches. Type in the first few letters of your search term and Find Suggest suggests words from the document that match.

Click on the image above for a closer look.

After installing Find Suggest the regular old CTRL+F search query looks the same as always. When you start typing a search term, however, you'll notice that suggested terms appear to the right of the query box—the highlighted words in the screenshot above. Clicking on the suggested word fills in the query box with your selection.